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Retinal arterial tone is controlled by a retinal-derived relaxing factor
1Department of General Physiology and Human Physiology and Pathophysiology, University of Gent, Belgium.
Circulation Research
|October 3, 1998
Summary
The retina releases an unknown factor that relaxes retinal arteries, significantly reducing smooth muscle cell tone. This heat-stable, diffusible molecule is not a known vasoactive substance.
Area of Science:
- Ophthalmology
- Vascular Biology
- Pharmacology
Background:
- Retinal arterial smooth muscle tone is crucial for ocular blood flow regulation.
- The precise mechanisms controlling retinal vasodilation are not fully understood.
Purpose of the Study:
- To investigate the influence of retinal tissue on retinal arterial smooth muscle cell tone.
- To identify potential novel vasorelaxant factors released from the retina.
Main Methods:
- Isolated bovine retinal arteries were mounted in a wire myograph.
- Isometric tension recordings were used to measure contractile responses.
- Retinal tissue was applied to contracted arteries, and incubation solutions were tested.
Main Results:
- Adhering retinal tissue significantly reduced contractions induced by prostaglandin F2alpha, U-46619, serotonin, and endothelin-1.
- A diffusible factor from retinal tissue induced complete relaxation of contracted retinal arteries.
- The relaxing factor was heat-stable, hydrophilic, and not nitric oxide, prostanoids, or known neurotransmitters.
Conclusions:
- The retina releases a novel, diffusible, heat-stable relaxing factor that modulates retinal arterial tone.
- This factor plays a significant role in regulating retinal vascular smooth muscle.
- Further research is needed to identify the chemical nature of this novel retinal relaxing factor.